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arXiv · hep-th/9702043

Graceful Exit and Energy Conditions in String Cosmology

Ram Brustein·Richard Madden
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Abstract

String cosmology solutions are examined in a generalized phase-space including sources representing arbitrary corrections to lowest order string-dilaton-gravity effective action. We find a set of necessary conditions for a graceful exit transition from a dilaton-driven inflationary phase to a radiation dominated era. We show that sources allowing such a transition have to violate energy conditions similar to those appearing in singularity theorems of general relativity. Since familiar classical sources, excepting spatial curvature, obey these energy conditions we conclude that a generic graceful exit in string cosmology requires a new effective phase of matter. Our results clarify and generalize previous analyses and enable us to critically reexamine proposed non-singular cosmologies.

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Ram Brustein, Richard Madden. 1997-02-05. Graceful Exit and Energy Conditions in String Cosmology. https://doi.org/10.1016/s0370-2693(97)00945-3

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